EV Gearbox Oil Level Control for High-Acceleration Efficiency
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Solution Overview
Problem
Existing electric vehicle transmission systems experience efficiency losses due to increased temperature and pressure of lubricating oil during high acceleration events, leading to churning and friction losses, which reduce the overall performance and range of the vehicle.
Innovation Solution
A transmission system that dynamically adjusts lubricating oil distribution by temporarily adding or removing oil from the gearbox during transient events, using a controller and pump to manage oil levels based on vehicle acceleration, thereby maintaining efficiency and reducing heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large amount of lubricating oil is present in the gearbox during high acceleration, then lubrication is improved, but churning losses and friction losses increase due to increased temperature and pressure
Solution Approach 1:
The system dynamically adjusts the amount of lubricating oil in the gearbox based on operating conditions. During high acceleration events, the pump transfers excess oil from the gearbox to the reservoir. During low acceleration events, oil is returned from the reservoir to the gearbox. This dynamic adjustment optimizes lubrication while minimizing energy losses from churning.
Solution Approach 2:
The controller receives acceleration signals from the vehicle's acceleration sensor and automatically controls the pump operation accordingly. When high acceleration is detected, the controller activates the pump to remove excess oil. When low acceleration occurs, the controller activates the pump to return oil to the gearbox, creating a closed-loop feedback system that responds to real-time operating conditions.
2Reliability
If lubricating oil is continuously circulated at high flow rates, then lubrication coverage is improved, but heat dissipation efficiency decreases due to increased temperature and pressure
Solution Approach 1:
Instead of continuous high-flow circulation, the system uses periodic oil transfer actions triggered by acceleration events. The pump operates intermittently to transfer oil during high acceleration and return oil during low acceleration periods. This periodic action maintains adequate lubrication coverage while reducing overall heat generation from continuous high-velocity circulation.
3Device complexity
If the gearbox operates with fixed oil levels, then system complexity is reduced, but efficiency losses occur during transient acceleration events
Solution Approach 1:
The system introduces an intermediary oil reservoir between the gearbox and the pump. This reservoir acts as a buffer that stores excess oil during high acceleration events and supplies oil during low acceleration events. The intermediary reservoir simplifies the control system by providing a natural storage mechanism, reducing the need for complex active control while maintaining efficiency during transient events.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances the operational efficiency of the gearbox during high acceleration by minimizing oil-related losses, thus increasing the vehicle's range and power output.
Implementation Method 1
a pump operable to transfer a portion of the lubricating oil from the reservoir to the gearbox when the vehicle acceleration is determined to be greater than a first predetermined value
Implementation Method 2
lubricating oil distribution by temporarily adding or removing oil from the gearbox during transient events
Data Source
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AI summary
A transmission system for an electric vehicle. The system includes a gearbox containing gears and a lubricating fluid. A pump is provided for supplying and removing lubricating fluid from the gear box. The operation of the pump is controlled by a controller. A reservoir is provided for storing lubricating fluid. The controller is configured to control the pump so that a portion of the lubricating fluid is removed from the gear box when the vehicle is involved in a high acceleration event.